header,
nav,
footer,
section {
  margin: 10px auto;
  background: #ccc;
  text-align: center;
  height: 100px;
  width: 1200px;
}
section {
  background: transparent;
  overflow: hidden;
}
section aside,
section article {
  height: 300px;
  background: #f00;
}
section aside:first-child {
  width: 200px;
  float: left;
}
section aside:last-child {
  width: 200px;
  float: right;
}
section article {
  margin: 0 5px;
  width: 790px;
  float: left;
}
.caller {
  width: 100%;
  height: 200px;
}
@media (max-width: 1200px) {
  header,
  nav,
  footer,
  section {
    margin: 10px auto;
    background: #ccc;
    text-align: center;
    height: 100px;
    width: 960px;
  }
  section {
    background: transparent;
    overflow: hidden;
  }
  section aside,
  section article {
    height: 280px;
    background: #f00;
  }
  section aside:first-child {
    width: 180px;
    float: left;
  }
  section aside:last-child {
    width: 180px;
    float: right;
  }
  section article {
    margin: 0 5px;
    width: 590px;
    float: left;
  }
  .caller {
    width: 100%;
    height: 200px;
  }
}
@media (max-width: 768px) {
  header,
  nav,
  footer,
  section {
    margin: 10px auto;
    background: #ccc;
    text-align: center;
    height: 100px;
    width: 480px;
  }
  section {
    background: transparent;
    overflow: hidden;
  }
  section aside,
  section article {
    height: 180px;
    background: #f00;
  }
  section aside:first-child {
    width: 80px;
    float: left;
  }
  section aside:last-child {
    width: 80px;
    float: right;
  }
  section article {
    margin: 0 5px;
    width: 310px;
    float: left;
  }
  .caller {
    width: 100%;
    height: 200px;
  }
}
@media (max-width: 480px) {
  header,
  nav,
  footer,
  section {
    margin: 10px auto;
    background: #ccc;
    text-align: center;
    height: 100px;
    width: 100%;
  }
  section {
    background: transparent;
    overflow: hidden;
  }
  section aside,
  section article {
    height: 110%;
    background: #f00;
  }
  section aside:first-child {
    width: 10%;
    float: left;
  }
  section aside:last-child {
    width: 10%;
    float: right;
  }
  section article {
    margin: 0 5px;
    width: 70%;
    float: left;
  }
  .caller {
    width: 100%;
    height: 200px;
  }
}
